The prominence of agencies in today’s digital marketing ecosystem is not surprising: the digital marketing landscape is so complex and seemingly all-encompassing that moving forward alone simply doesn’t seem like a viable option.

Agencies aren’t perfect, however, and companies that believe they can simply outsource digital marketing to another firm often learn the hard way that it’s not so simple.

No two businesses are the same, so what gets outsourced and what remains in-house will obviously vary from company to company. But all businesses with in-house marketing staff face many of the same challenges.

Here are seven of the most painful:

1. Recruiting

Recruiting a stellar marketing person to join your team may not be as difficult as recruiting a top-notch web developer, but don’t tell that to the individual responsible for your recruiting efforts. Finding good marketing people is difficult, particularly for smaller companies hoping to hire one person who can handle multiple responsibilities for efforts involving numerous (read: all) digital channels.

2. Insufficient training and mentoring

Companies looking for a jack-of-all-trades marketer who is as knowledgeable and experienced with, say, SEO as she is with social are probably going to be disappointed. Few in-house marketing hires come equipped with everything you’ll want or need, making training and mentoring a must.

Unfortunately, many companies fall short in capturing the knowledge their marketing teams obtain and establishing the formal and informal channels necessary for sharing it across the marketing organization, including with new and younger employees.

3. Lack of strategic direction

While agencies are asked to do many things, one of the most important is helping clients establish an appropriate strategic direction for their marketing efforts. Some companies trying to do more in-house, however, fail to adequately address strategy at the appropriate levels.

The end result: talented in-house marketing teams are set up to fail because key strategy pieces that need to come from management or have management buy-in are not in place.

4. Bandwidth constraints

Relatively few companies can build what amounts to an in-house full-service agency, so one of the biggest constraints in-house marketing teams face is bandwidth. Unfortunately, a lack of bandwidth can be extremely detrimental; in many cases, when there’s too much to do, nothing meaningful gets done.

5. Staying ahead of the curve

Digital marketing channels are increasing in number and complexity. Best practices are evolving, when they even exist. And the channel-specific tools that promise to make everything work are overwhelming. All this makes it incredibly difficult for in-house marketing teams to stay ahead of the curve. In fact, in most cases, staying ahead of the curve seems like a pipe dream; at many businesses, the name of the game is catch-up.

6. Funding for technology

The increasingly complex digital marketing landscape is challenging for everybody and while technology is not a panacea, digital tools obviously have a role to play in managing digital campaigns.

For many companies, of course, the cost of those tools puts them out of reach, meaning internal marketing staff don’t have some of the capabilities that would promote efficiency and success.

7. Unrealistic expectations

When it comes to what marketing campaigns can do, and how quickly, executives often have big expectations. Which is understandable: sales and marketing are crucial to the success of most businesses, so it seems appropriate to set the bar for these higher than lower. But there’s a fine line between optimistic expectations and unrealistic expectations, and unrealistic expectations can have ill effects on those responsible for executing marketing campaigns.

To be sure, companies that rely on agencies frequently come to the table with unrealistic expectations, but for obvious reasons, in-house marketing teams often have less of an ability to push back against expectations that reasonably can’t be met.